Validation of Envisat MERIS algorithms for chlorophyll retrieval in a large, turbid and optically-complex shallow lake

• DOI: 10.1016/j.rse.2014.07.024
• Publication Date: 2014-08-29T21:08:50Z
• Authors: Stephanie C.J. Pa...; Peter D. Hunter; Thomas Lankester; Steven Hubbard; Evangelos Spyrakos; Andrew N. Tyler; Mátyás Présing; Hajnalka Horváth; Alistair Lamb; Heiko Balzter; Viktor R. Tóth
• Keywords: Imaging spectrometer

The 10-year archive of MEdium Resolution Imaging Spectrometer (MERIS) data is an invaluable resource for studies on lake system dynamics at regional and global scales. MERIS are no longer actively acquired but their capacity scale monitoring lakes from satellites will soon be re-established through the forthcoming Sentinel-3 Ocean Land Colour Instrument (OLCI). development validation in-water algorithms accurate retrieval biogeochemical parameters thus key importance if potential OLCI to fully exploited monitoring. This study presents first extensive chlorophyll-a (chl-a) by in highly turbid productive waters Lake Balaton, Hungary. Six chl-a over optically complex Case 2 waters, including band-difference neural network architectures, were compared using 2007–2012. locally-tuned validated situ (n = 289) spanning five year processed image time series all four basins. In general, both tested (Fluorescence Line Height (FLH) Maximum Chlorophyll Index (MCI)) performed well, whereas processors generally found much less accurately retrieve concentrations. Level 1b FLH algorithm best overall terms (R2 0.87; RMSE 4.19 mg m− 3; relative 30.75%) particularly concentrations ≥ 10 3 0.85; 4.81 20.77%). However, under mesotrophic conditions (i.e., < 3) was outperformed FUB/WeW processor (relative 57.57% versus 46.96%). An ensemble selection demonstrated improve retrievals.